city police commissioner batts will have a conference at 6:30 telling us how the city will react. joce sterman did a breakdown of all the local run ares in boston. we're on top of this story on twitter on facebook on tv mall night long. have a safe night and we'll see you back here at 11. >>> this is a special edition of "world news." tonight, terror in boston. bombs explode at the marathon. the first explosion as runners cross the finish line. seconds later, a fiery second blast. >> a blast of fire and smoke and i just ran as fast as i could. >> injured spectators, children raced to the hospital, harrowing scenes on the pavement. >>> tonight, the latest from the terror investigator, the response from washington,